2TH PWR

iTrader: (21)

Before I attempt a resolution I just wanted to get the opinions on a problem I've been having.

Synopsis of facts.
2003 350Z.

- oil burning. Has been present and relatively light for a couple of years. But I never got a CEL and and it wasn't too big an issue so I just changed oil and really the car was a total garage queen.

the past year I started beating the car up at track days and I also installed some ART pipes. Blue smoke is now obtrusive. Brown oil coats my rear bumper. I go through 3-4 L in 1000 km of hard use. Smoke is worst at first start and at WOT, sometimes when pulling away from a stop.

I pulled my plugs for a 2 year change in March and they looked like this.
Hi, we are cyllinder 1, 2, 3, 5, 6. we are a little over 2 years old and we are kinda white and chalky.


I am cyllinder 4 and I am coated in oil and black crud,


I also noticed some brief hesitation occaisionally at WOT in 4th and 5th at the track, but it was sporadic.

I have also started getting misfire codes from cyl 4.

To keep my track days going I have been resorting to changing the oil everyday, and replacing the plug every day.

After one very extreme track event where speeds were very high (routinely over 120mph on a converted airport circuit cyl 4 spark plug looked like this. This is 2 track days and less than 1000kms.


So today I did a dry compression test. (did not pour a cap of oil into cyllinders)
Rear engine
Cyl 5 170 psi Cyl 6 172 psi
Cyl 3 156 psi Cyl 4 175 psi (Cyl 4 is the one with the black oil coated plug)
Cyl 1 140 psi Cyl 2 158 psi
Front engine

So the results of the compression test were super weird. I was hoping changine the valve seals would stop the oil getting into cyl 4 and causing detonation/ misfiring.

Anyways before I proceed experienced advice would be appreciated.
Side note, acceleration still feels strong for the most part.

This was my track video from Sunday July 15th.
Skip to 3:20 as everything before that is just me screwing around.

2TH PWR

iTrader: (21)

I forgot to add, those two shots of the cyl 4 plug were the worst two. (one 2 years old, and one after very heavy use)Typically if I change the plug after 1 track day at a less intense track the gap is not affected visually, although I do get the P0300 random misfire code. It's coated in a thin layer of black carbon, and it's also covered in oil on the inside. You can see the threads have oil in them too.

1 track day use. get misfire code at end of day.

Lee R

iTrader: (10)

#4 plug looks like a cylinder issue. Do a leak down test next to see the shape of your pistons because it looks like blowby past the piston and not your valve seals on that one.